A hack into Twitter's back-end productivity applications earlier this month is raising some serious questions -- not only about password system security itself, but also about some consequences of network intrusion that may have been unforeseen. About a month ago, a hacker was able to access a Twitter employee's personal email account, according to a blog post by Twitter cofounder Biz Stone. Once there, the hacker struck the mother lode: access to the employee's Google Apps account, which contained Docs, Calendars and other Google Apps that Twitter uses.

In several articles I've seen the Twitter execs dismiss blame that people might want to put on Google. Most likely the user that got "hacked" was using a weak password that involved publicly available information.